Recently, a robot surgery have been studied and introduced to reduce the pain of patients and to recover faster in an endoscopic surgery or an otolaryngology surgery (ENT surgery).
In such a robot surgery, in order to minimize a risk of the surgery and to operate the surgery more precisely, a navigation system is used to navigate to an exact lesion of a patient by tracking and detecting a spatial position and direction of a target such as lesion portion or surgical instrument.
The navigation system described above includes a tracking system which is capable of tracking and detecting a spatial position and direction of a target such as lesion or surgical instrument.
The tracking system described above includes a plurality of markers attached on a lesion or a surgical instrument, a first and second image forming units to form images of lights provided by the markers, and a processor calculating a 3-dimensional coordinates of the markers which are coupled to the first and second image forming units and calculating a spatial position and a direction of the target by comparing pre-stored information of straight lines connecting the markers adjacent to each other and angle information formed by a pair of straight lines adjacent to each other with the 3-dimensional coordinates of the markers.
A conventional tracking system and method as described above uses diameters of a circle of the markers formed on the image forming unit to calculate separated distances between the markers through the processor. But, a border of circle of the marker is opaque by a distortion of a lens of the image forming unit, it is difficult to calculate exactly the diameters of the circle of the markers, as well as, exact positions of the markers since a change of diameters of the markers are slight and hard to distinguish.